Extendable retractable barrier

Abstract

A protective barrier for use on a baseball field that is actuated by motion sensors that are housed within a structured base. The protective barrier is actuated when a projectile such as a baseball travels through the sensors line of sight. The barrier serves to sense when a line drive is hit towards a pitcher and will rapidly extend to block the baseball and greatly reduce the possibility of harm to the pitcher.

1. An extendible retractable barrier for protecting a baseball pitcher from line drives comprising:
 a) a subterranean housing having a top portion flush with the ground; 
 b) a rigid screen member disposed within said housing; 
 c) means for vertically extending and retracting said rigid screen member so a substantial portion thereof can be situated above ground as needed; 
 d) sensor means for detecting the approach of a projectile approaching said screen and activating said means for extending said screen prior to said projectile surpassing said screen, wherein said extending and retracting means is a chain drive assembly, said chain drive assembly comprising:
 i) a reversible motor having a drive shaft; 
 ii) a bearing block spaced vertically apart from said motor; 
 iii) a drive chain communicating between said drive and said bearing block; and 
 iv) a screen mounting bracket affixing said drive chain to said screen. 
 
 
   
   
     2. An extendible retractable barrier as recited in  claim 1 , wherein said sensors are in electrical communication with said motor and actuate said motor when activated. 
   
   
     3. An extendible retractable barrier as recited in  claim 2 , wherein said sensors are disposed on the ground level, top portion of said housing and oriented upward to detect the presence of an overhead projectile approaching the vertical axis of said screen. 
   
   
     4. An extendible retractable barrier as recited in  claim 3 , wherein said projectile is a baseball. 
   
   
     5. An extendible retractable barrier as recited in  claim 4 , wherein said housing is subterraneanly disposed within the field of play of a baseball field. 
   
   
     6. An extendible retractable barrier as recited in  claim 5 , wherein said housing is disposed in-line between home plate and the pitching rubber of the pitching mound. 
   
   
     7. An extendible retractable barrier as recited in  claim 6 , wherein said housing is located substantially 15 feet from said pitching mound. 
   
   
     8. An extendible retractable barrier as recited in  claim 7 , wherein said sensors have a limited range for detecting the baseball thereby preventing the activation thereof in the event of a pop fly. 
   
   
     9. An extendible retractable barrier as recited in  claim 8 , wherein a line drive hit in-line from said home plate towards the pitching rubber of the pitching mound will activate said sensors. 
   
   
     10. An extendible retractable barrier as recited in  claim 9 , wherein said sensors actuate said motor thereby initiating the high speed rotation of said drive shaft. 
   
   
     11. An extendible retractable barrier as recited in  claim 10 , wherein the rotation of said drive shaft rotates said drive chain thus propelling said screen upwards at a rapid rate. 
   
   
     12. An extendible retractable barrier as recited in  claim 11 , wherein said screen is extended rapidly enough to impede the projection of said ball towards said pitching mound thereby effectively protecting said pitcher from injury. 
   
   
     13. An extendible retractable barrier as recited in  claim 12 , wherein said housing further includes a timer mechanism thereby allowing said screen to remain in the extended position for a pre-determined period of time after deployment before said motor reverses and retracts said screen. 
   
   
     14. An extendible retractable barrier as recited in  claim 1 , wherein said housing includes a manual override to turn said sensors on and off and to extend and retract said screen as needed. 
   
   
     15. An extendible retractable barrier as recited in  claim 1 , further including a remote control device to allow the user to extend and retract said screen as needed from a remote location.